This invention relates to collagen and more particularly to oligopeptides derived from collagen.
"Natural insoluble collagen" as used herein means and refers to collagen which cannot be dissolved in an aqueous alkaline or in any inorganic salt solution without chemical modification and includes hides, splits, and other mammillian or reptilian coverings. More particularly, "natural insoluble collagen" means and refers to the corium which is the intermediate layer of a bovine hide between the grain and the flesh sides.
Collagen constitutes the connective tissue and is the major type of fibrous protein in higher vertebrae. Collagen in its natural state exists in a triple chain helix along with a constant periodicity between aligned triple chains. The triple helical configuration of collagen is sometimes referred to as a fibril and the fibrils align with an axial periodicity of about 640 A.
Although there are several types of collagen, the major type is referred to as "type I" which is the major collagen of skin, bones and tendons. The type I collagen has a chain composition of [.alpha.1(I).sub.2 .alpha.2]. The .alpha.1(I) and .alpha.2 chains are homologous.
In young animals there is little intermolecular and interfibrilar crosslinking which provides for some degree of solubility of the collagen. However, during the aging process both intermolecular and interfibrilar crosslinking occurs, thus making the collagen insoluble.
The collagen and related materials have found utility in the food, cosmetic and pharmaceutical fields. More particularly, in the nutritional field it is known that protein which has been enzymatically digested can be used for nutritive purposes; however, the residual enzymes in the predigest have various undesirable effects.
Further, it is known to sever collagen chains into oligopeptides by treating the collagen with strong base; however, the oligopeptides produced are somewhat impure and are not particularly adapted for food purposes.
In accordance with the present invention a process for preparing oligopeptides from collagen is provided which removes substantially all the impurities therefrom and does not require enzymatic digestion.